The present invention relates to a guide chain capable of guiding and protecting cables, tubes, etc.
Guide chains are used in machines having movable parts, e.g., robots, so as to prevent entanglement of cables, tubes, hoses, etc., which are connected to the movable parts.
A conventional guide chain includes a plurality of link modules made of synthetic resin, and the link modules are pivotably connected by fitting a pin into a hole of the adjacent link module. An angle between the adjacent link modules is limited. With this structure, the guide chain is capable of guiding cables without folding them.
In the conventional guide chain in which the link modules are connected by the pin-hole connecting mechanism, the link modules pivot on the pins when a movable part, to which the guide chain is connected, is moved. Since the link modules pivot many times, the pins and inner faces of the holes are abraded, and resin dusts formed by abrasion contaminate surroundings. If the guide chain is used in a clean room, the resin dusts badly influence products.
In the conventional guide chain in which the link modules are connected by the pin-hole connecting mechanism, the pins collide with the inner faces of the holes, so that noise is generated while the guide chain is moved. To reduce noise, link modules made of resin including reinforcing fillers or elastic resin including no reinforcing fillers were proposed. However, in the guide chains made of the elastic resin, noise can be effectively reduced, but they do not have enough toughness. Namely, the guide chains made of the elastic resin cannot be applied to machines, which move the guide chains at high speed with high load.
To solve the problems of the conventional guide chain in which the link modules are connected by the pin-hole connecting mechanism, guide chains, in which link modules can pivot without using the pin-hole connecting mechanism, were proposed (see Japanese Patent Gazettes No. 09-177902 and No. 2001-3997). In the guide chains, link modules are serially pivotably connected by elastic connecting members or elastic hinge members.
However, in the guide chains disclosed in the Japanese Patent Gazettes, additional link modules cannot be connected, so length of the guide chains cannot be adjusted according to machines. And, if one of link modules is broken, the guide chain must be completely exchanged. Further, curvature of turning the guide chain cannot be changed, and the guide chain cannot be reversely turned.